Field of the Invention
The present invention relates to visualization of image information for checking an exposure state of captured image data.
Description of the Related Art
As one method of visualizing information on exposure of captured image data, the histogram display technique is known as a conventional technique. The histogram display technique makes it possible to visually check a distribution state of luminance values in captured image data by plotting the luminance values that occur in the captured image data on a two-dimensional plane on which, for example, the horizontal axis represents the luminance value and the vertical axis represents the frequency.
Japanese Patent Laid-Open No. 2008-172732 has disclosed a method of displaying a histogram in a size in accordance with a detected area by detecting the area of a main subject of interest in image data in order to determine whether the exposure of the main subject of interest is appropriate.
However, captured image data generally includes noise even though noise reduction processing is performed on the captured image data. Because of this, by the method described in Patent document 1, the generated histogram is affected by noise and there is a case where it is difficult to check the exposure state.
In view of the above, an object of the present invention is to generate a histogram for accurately grasping an exposure state of captured image data.